This year is the first time I've applied for Majors, and looking up the GLT's past winners not many of them seem to have kept the secret weapons for long, or developed them much further. I'm just going to do a quick writeup of what you could do with the secret weapons on various teams to give ideas to people :P

Most races will have G access only on their linos, which leaves us with fairly bog standard considerations on skill access. Block/Tackle/Strip ball on your ball and chain, block/dirty player on the chainsaw, not many great options for the bomma, and a wrackle obligatory choice on the Pogo, which is probably the strongest option as it saves you two skill slots on sacker builds (and most teams don't even have VLL access).

I lumped together elves, races with bog standard unskilled linemen, stunties and undead teams because there really isn't a lot of variation there in terms of development options. Different teams might have different overall sinergies with the various secret weapons in terms of how much they can stall and consequently how long they can keep the SWs on the pitch.

Amazons
1) Ball and Chain. You start with dodge, but after the first 2/3 skills you probably start hoping for doubles. A solid addition to the team.
2) Bombardier. AG3, no particularly good skill access, would probably pick something else.
3) Chainsaw. Like a goblin chainsaw but starts with dodge, G access and higher strength. 70k for an ST3 nobbla blackwart? Yes please.
4) Pogo Stick. This could probably be the strongest option, leaping on a 3, wrestle/tackle/strip ball/frenzy access, just needs an 11 to become a truly amazing sacker. You don't need Roxy when you got this babe.

Chaos Chosen
1) Ball and Chain. Horns is useless now, BUT you get a truly unstoppable beast if you can get the MVPs and the CAS rolling. Block, Claw, Might Blow, Stand Firm, Tentacles, possibly Guard or Tackle? Anybody who's played Pestilens in secret league know what a tentacles/clawMB Ball&Chain player can do.
2) Bombardier. Strong Arm access could possibly be his saving grace. Still not great.
3) Chainsaw. Block access, but beyond that, no use for either S or G at all. I'd rather induce Max.
4) Pogo Stick. Remember when you rolled a double and picked leap because it sounded fun, and then used up another skill to get VLL and then had to build the whole sacking stack on top of that? That never happened because you took dodge or leader. This chap can just go wrestle/tackle/frenzy/strip ball right from the start because he's got the basics already figured out.

Chaos Dwarf, Humans, Norse, Vampires, Orcs
I'm putting all these races together even though some might have higher chances to survive for longer, as the development options are the same.
1) Ball and Chain. Just G access but still a solid choice, slightly weaker than the two above races.
2) Bombardier. At least he is not a stunty. Meh.
3) Chainsaw. A brilliant fouler.
4) Pogo Stick. Same G access sacker as the others, but with no dodge/horns/whatever on top to make it stand out.

Chaos Renegade
1) Ball and Chain. Refer back to the Chaos Chosen entry, it even costs 10k less.
2) Bombardier. This one is possibly the best in the game as it has HMP access on normal rolls! I'm not a fan of the bomma on non-elven teams but this one just needs 6 spps to become a staple on defense.
3) Chainsaw. You probably already have a dirty player and a dedicated blitzer. You might not have enough reasons to take this over the bomma or the B&C.
4) Pogo Stick. I would say that it's the same as the goat above, but it starts without horns, and you might have already developed your own rat sacker along similar lines. Still a good choice as it saves you 2 skill slots.

Dark Elf, actually, Any Elves, really
1) Ball and Chain. The first one we see with GA access. Blodgestep/sprint/sure feet. Probably changes the timings of when you score and how you setup. Might not sync well with the team.
2) Bombardier. 2+/3+ bomb up to 6 squares, fumbling only on 1s is really nice.
3) Chainsaw. Really cool but worth the 70k/90k with DP in order to foul some lino?
4) Pogo Stick. Saves you two skill slots

Dwarf
1) Ball and Chain. Block, tackle start with S access really makes it interesting. That lino didn't even become noticeably slower and really makes your offense better, great cage corner on offense, or possibly a great roadblock against a slow opponent on defense. If you have a Deathroller as well, you can do a tag team or keep one per half.
2) Bombardier. Move along, Eziasson's cheaper.
3) Chainsaw. Reasonably priced and non-loner version of the Star Player whose name now escapes me. Probably because nobody ever takes him.
4) Pogo Stick. This is probably the first time the Pogo looks less appealing than the other choices. I get the wildcard appeal, but are you really going to roll that 4+ Leap when it comes to it?

Stunties (Ogre, Goblin, Halfling)
1) Ball and Chain. Sprint/sure feet and, if you're not a Gnoblar, side step. All well and good but you don't get block or even the S skills a normal Fanatic would get. But... Your B&C is still RIGHT STUFF. DO I NEED TO REPEAT THAT?
2) Bombardier. Apart from a Goblin team wanting to field 3 of them with Dribblesnot on call, don't really see the appeal.
3) Chainsaw. Love it. BTW, also still right stuff.
4) Pogo Stick. Brilliant addition to any team really.

Tomb Kings of Khemri/Shambling Undead/Necromantic Horrors
1) Ball and Chain. Not the best B&C in this list but definitely not horrible. Regen could also keep him alive for longer.
2) Bombardier. Only a double can save this chap from being useless.
3) Chainsaw. Yes please!
4) Pogo Stick. Even funnier than the Dorf one. At least he's cheap!

Lizardmen
1) Ball and Chain. Similar to the Stunty teams option but it cannot be thrown.
2) Bombardier. Please don't.
3) Chainsaw. MA8 BZZZ will make people hate you. Sadly it won't last long.
4) Pogo Stick. Definitely the strongest option.

Nurgle
1) Ball and Chain. GM access really just boils down to block/tentacles/claw. Unfortunately he's not a goat so he can't have the ST stack that really makes him a monster.
2) Bombardier. I'd mention that with the Disturbing Presence you bring, it should be almost impossible to intercept it on anything but a 6.
3) Chainsaw. Do take this.
4) Pogo Stick. Similar to what was said about the bog standard 40k/50k linemen at the start, but with the added bonus of mutation options, and the Decay skill that will kill him faster than any other team's pogoes. This is true for all the other secret weapons, Nurgle is really not going to benefit from the GLT for long.

Skaven
1) Ball and Chain. G access as normal but watch out for those doubles in order to become a proper monster through mutations. Suffers from the Kreek Rustgouger syndrome, really good on paper but if he's on the pitch for a whole half it means that things might not be going well for you.
2) Bombardier. It could be useful on defense, I'll give you that.
3) Chainsaw. Rats really should have a chainsaw star player. And by star player I mean Dirty Player.
4) Pogo Stick. This is really good, no question, considering the fact that it won't be sent off. Make him your sacker and save those precious Gutter Runners for retrieval duties. It will also cost much less than your tooled up stat freak/doubleskilled GR.

Slann
1) Ball and Chain. Can't leap anymore, sorry. Bog standard G access lino but there's not many other options in this list for the frogs.
2) Bombardier. Meh. See the standard commentary.
3) Chainsaw. You CAN still leap. Please do that.
4) Pogo Stick. Hehehe. Sadly you can't give it to the kroxigor. Maybe if it allowed you to leap twice...

Underworld
1) Ball and Chain. It's a stunty B&C that is still Right Stuff and has M and A access. Don't ignore this opportunity. This gobbo has the chance of becoming better than Kreek.
2) Bombardier. You miss the gobbo shenanigans? Take the chainsaw.
3) Chainsaw. VLL and Leap access on normals. Why are you even asking?
4) Pogo Stick. Could be useful, even if only as a one turner. I'd still take Chainsaw and B&C.



EDIT/Note/TL;DR
Grotty's Little Tournament allows the winners to take their 2 picks of 4 secret weapon options, on 2 unskilled linos. The options are Bombardier, Chainsaw, MA3/ST7/Ball&Chain, VLL+Leap.